This invention relates to fabricating pigtailed LED assemblies and more particularly to method and apparatus for aligning the end of an optical fiber in the concave emitting well in an LED.
A light emitting diode (LED) is commonly employed as the source of light in the transmitter of a fiber optic communication system. In order to maximize the amount of light available for transmission in the fiber transmission lines of the system, an assembly is fabricated with a fiber pigtail precisely aligned in the emitting well of the LED. The practice is to secure the fiber to the side of a micro-manipulator with two tweezers that are vertically spaced approximately three inches apart. Each of the tweezers lightly clamps the fiber at what approximates a point contact, with the lower-one end of the fiber being adjacent the emitter surface of the LED. After the micro-manipulator is operated to obtain the maximum transmission of light in the fiber, an epoxy resin is poured into the chimney of a support member associated with the LED for fixing the orientation of it and the fiber. It has been found that there is normally a bow in the unsupported length of fiber between and below the two tweezers which makes it difficult to precisely align the one end of the fiber in the emitting well of the LED so as to obtain maximum transmission of light in the fiber. An object of this invention is the provision of improved method and apparatus for fabricating pigtailed LED assemblies.